The following description relates to human interface and input systems for electronic devices, particularly hand-held electronic devices, such as cell phones, personal digital assistants (“PDAs”), pocket personal computers, smart phones, hand-held game devices, bar-code readers, remote controls, and other similar input devices having a keypad or one or more input elements.
Electronic devices have become increasingly sophisticated and physically smaller due in part to a decrease in the price of processing power and a concurrent increase in demand by consumers for smaller devices. Such devices, however, tend to be limited in function and utility by the user's ability to interface with the device for data input (e.g., text, numeric, and functional input) and/or device control, which becomes increasingly more difficult to do as the available space on the device's surface for positioning the input elements, which are used for data input and/or device control, continues to decrease.
Various human interface and input systems and techniques for hand-held electronic devices have been developed for data input and device control. These include miniature keyboards and keypads used in combination with chordal input techniques, modal input techniques and/or smart keys; and touch screens used in combination with on-screen keyboard or keypad software or hand-writing recognition software.
Keyboard or Key Pad Used with Chordal, Modal and Smart Key Techniques
Miniature keyboards and keypads are similar to their standard full-size versions—i.e., a keyboard generally has a full set or substantially full set of numeric, character, and functional input elements, while key pads typically have a reduced set of numeric, character and/or functional input elements compared to keyboards. These miniature input devices typically are designed to fit the available space on one surface of a hand-held electronic device or are designed as small, easily transportable, external plug-in devices. Thus, as hand-held electronic devices become smaller, the size of the input elements typically has been reduced in order for the desired number of input elements to fit on one surface of the electronic device.
For data input and device control, miniature keyboards and keypads typically either require one of two input techniques—use of one or more thumbs or fingers to press the desired input elements or use of a stylus to “peck” the desired input elements (which is usually done where the input element is of smaller size). Various techniques, such as chordal input techniques, modal input techniques and smart keys, have been developed and implemented to improve the efficiency and effectiveness of using miniature keyboards and keypads.
Chordal Input Techniques
Chordal input techniques generally are based upon the principle that characters, symbols, words, phrases or concepts can be represented by a reduced set of input elements. Thus, by only having to press a reduced combination of input elements, functionality can be increased and quicker and more accurate data input can be realized. Chordal input techniques can be used on any keyboard or keypad configuration or any device having more than one input element, and typically results in fewer input elements or more functions compared to conventional keyboards or keypads. An example of an electronic device using two-handed chordal input techniques is a court reporter or stenographer's typewriter. One chordal input technique using a keypad to decrease the number of actuations to achieve a large number of functions is described in U.S. Pat. No. 5,973,621 to Levy, entitled “Compact Keyed Input Device,” which is incorporated herein by reference.
Modal Input Techniques
Modal input techniques are based on the concept that functions of the electronic device, e.g., text messaging in a cell-phone or PDA, can be accessed by pressing a particular input element (or combination of elements) on a keyboard or keypad. Once that particular input element is pressed, the functionality of all or a portion of the input elements on the keyboard or keypad may change. Modal techniques typically are used in calculators, cell-phones, and PDAs. For example, in cell phones, a modal technique called multi-tap is common, in which individual input elements on the keypad are associated with multiple symbols, such as characters, letters, numbers, icons or other types of symbols, which tends to reduce the number of input elements required to achieve the desired functions, e.g., a twelve-input-element keypad can be used to represent all letters of the English alphabet and the decimal digits. A user can input a desired symbol within a set of symbols associated with a certain input element by tapping on that particular input element with a thumb, finger, or stylus, one or more times to input the desired character. Thus, if a user desires to send a text message, the user may press a functional input element, e.g., a mode key, to access the text messaging functionality of the cell phone and then tap an individual input element one or more times to select the associated symbol for input. The number of taps needed to input a particular symbol may differ depending on the language character set chosen. For example, Japanese keypad or keyboards typically require a minimum set of 46 characters for text input, while English or American keyboards and keypads usually require a minimum set of 26 characters for text input. These modal input techniques have gained some popularity as users perform more text functions.
Smart Keys
Smart keys are typically used on keypads and refer to a single key or combination of keys that, when pressed, predict the users next logical action. Some implementations work better than others and some applications reduce the number of keystrokes required to complete a function better than others. Word-predictor software, for example, attempts to predict the word or character the user intends to input based upon one or more letters inputted by the user and the likely probabilities within a given language. The probability of the software guessing correctly increases with the length of the word or number of letters or characters inputted. In a device using smart keys on the keypad, a user may tap the keys 2, 2 and 8 in sequence to generate the word “cat” and the device would display that word first because it is usually the most common combination, whereas the word “bat,” which can be generated by pressing the same keys, would not be displayed first because it is not as common. Also, the word “cat” may be displayed after pressing the 2 key the second time based on a guess by the word-predictor software.
Smart keys also are typically used for Japanese data input where a user phonetically inputs letters representing the sound of the Japanese character (e.g., a Kanji character). Based on the inputted letters, the predictor software guesses the Japanese character. To select the character, a user would press the accept button or use the scrolling function to go to the next character with a similar set of phonetic inputs.
Touch Screen Using On-Screen Keyboard or Handwriting Recognition Software
Using on-screen keyboard or keypad software with a touch screen offers users the ability to enter data with fingers or thumbs on a screen-sized keyboard or buttons, allowing faster data input without a stylus or physical keyboard or keypad accessory; while using handwriting recognition software with a touch screen, such as GraffitiÔ on the Palm operating system, offers users the ability to enter text with a stylus by writing the text directly on the touch screen. Touch screens usually consume more power and are more expensive than non touch-sensitive screens. This higher power consumption can be a problem for hand-held electronic devices, which typically have limited power resources. Moreover, touch screens usually require the user to use both hands (e.g., one hand is used to hold and steady the device while the other hand is used to grasp the stylus), which is generally undesirable for interfacing with and controlling one handed hand-held electronic device, such as cell phones. Handwriting recognition software has improved the slowness and awkwardness inherent in stylus, finger or thumb input but other drawbacks still remain, such as high power consumption, the necessity to use both hands, and lack of tactile feedback to inform a user when an input element has been. Moreover, recognition software requires training to use properly, and, even then, still results in a high error rate.
Game Control
For game control, many of the above approaches have been used, but in most hand-held electronic devices, a user typically controls game play through the use of some form of input element, such as on a miniature keypad and/or directional pad (“D-pad”), which typically is located on the front surface of the device. Game control on some hand-held electronic devices, such as cell phones, is inherently one handed or at most two thumbed because of the size of the device, while game control on other hand-held electronic devices, such as PDAs and conventional game console controllers, is typically two-handed. The input elements associated with game control on these devices are typically digital even though analog input elements have been used on game controllers for PC and console game systems, such as Microsoft's Xbox or Sony's Play Station 2.